sata_mv Use DMA memory pools for hardware memory tables.
Create module-owned DMA memory pools, for use in allocating/freeing
per-port
command/response queues and SG tables. This gives us a way to guarantee we
meet the hardware address alignment requirements, and also reduces
memory that
might otherwise be wasted on alignment gaps.
Signed-off-by: Mark Lord <mlord@xxxxxxxxx>
--- old/drivers/ata/sata_mv.c 2008-01-24 12:40:10.000000000 -0500
+++ new/drivers/ata/sata_mv.c 2008-01-24 14:17:39.000000000 -0500
@@ -107,14 +107,12 @@
/* CRQB needs alignment on a 1KB boundary. Size == 1KB
* CRPB needs alignment on a 256B boundary. Size == 256B
- * SG count of 176 leads to MV_PORT_PRIV_DMA_SZ == 4KB
* ePRD (SG) entries need alignment on a 16B boundary. Size == 16B
*/
MV_CRQB_Q_SZ = (32 * MV_MAX_Q_DEPTH),
MV_CRPB_Q_SZ = (8 * MV_MAX_Q_DEPTH),
- MV_MAX_SG_CT = 176,
+ MV_MAX_SG_CT = 256,
MV_SG_TBL_SZ = (16 * MV_MAX_SG_CT),
- MV_PORT_PRIV_DMA_SZ = (MV_CRQB_Q_SZ + MV_CRPB_Q_SZ + MV_SG_TBL_SZ),
MV_PORTS_PER_HC = 4,
/* == (port / MV_PORTS_PER_HC) to determine HC from 0-7 port */
@@ -701,6 +699,33 @@
*/
static int msi; /* Use PCI msi; either zero (off, default) or
non-zero */
+/*
+ * These consistent DMA memory pools are owned by this module,
+ * and shared among all device instances. This gives us guaranteed
+ * alignment for hardware-accessed data structures, and low memory
+ * waste in accomplishing the alignment.
+ */
+static struct dma_pool *mv_crpb_pool;
+static struct dma_pool *mv_crqb_pool;
+static struct dma_pool *mv_sg_tbl_pool;
+
+static void mv_free_pool_items(struct ata_port *ap)
+{
+ struct mv_port_priv *pp = ap->private_data;
+
+ if (pp->sg_tbl) {
+ dma_pool_free(mv_sg_tbl_pool, pp->sg_tbl, pp->sg_tbl_dma);
+ pp->sg_tbl = NULL;
+ }
+ if (pp->crqb) {
+ dma_pool_free(mv_crqb_pool, pp->crqb, pp->crqb_dma);
+ pp->crpb = NULL;
+ }
+ if (pp->crqb) {
+ dma_pool_free(mv_crqb_pool, pp->crqb, pp->crqb_dma);
+ pp->crqb = NULL;
+ }
+}
/* move to PCI layer or libata core? */
static int pci_go_64(struct pci_dev *pdev)
@@ -1110,8 +1135,6 @@
struct mv_host_priv *hpriv = ap->host->private_data;
struct mv_port_priv *pp;
void __iomem *port_mmio = mv_ap_base(ap);
- void *mem;
- dma_addr_t mem_dma;
unsigned long flags;
int rc;
@@ -1119,37 +1142,21 @@
if (!pp)
return -ENOMEM;
- mem = dmam_alloc_coherent(dev, MV_PORT_PRIV_DMA_SZ, &mem_dma,
- GFP_KERNEL);
- if (!mem)
- return -ENOMEM;
- memset(mem, 0, MV_PORT_PRIV_DMA_SZ);
-
rc = ata_pad_alloc(ap, dev);
if (rc)
return rc;
- /* First item in chunk of DMA memory:
- * 32-slot command request table (CRQB), 32 bytes each in size
- */
- pp->crqb = mem;
- pp->crqb_dma = mem_dma;
- mem += MV_CRQB_Q_SZ;
- mem_dma += MV_CRQB_Q_SZ;
-
- /* Second item:
- * 32-slot command response table (CRPB), 8 bytes each in size
- */
- pp->crpb = mem;
- pp->crpb_dma = mem_dma;
- mem += MV_CRPB_Q_SZ;
- mem_dma += MV_CRPB_Q_SZ;
-
- /* Third item:
- * Table of scatter-gather descriptors (ePRD), 16 bytes each
- */
- pp->sg_tbl = mem;
- pp->sg_tbl_dma = mem_dma;
+ pp->crqb = dma_pool_alloc(mv_crqb_pool, GFP_KERNEL, &pp->crqb_dma);
+ if (!pp->crqb)
+ goto out_alloc_failed;
+
+ pp->crpb = dma_pool_alloc(mv_crpb_pool, GFP_KERNEL, &pp->crpb_dma);
+ if (!pp->crpb)
+ goto out_alloc_failed;
+
+ pp->sg_tbl = dma_pool_alloc(mv_sg_tbl_pool, GFP_KERNEL,
&pp->sg_tbl_dma);
+ if (!pp->sg_tbl)
+ goto out_alloc_failed;
spin_lock_irqsave(&ap->host->lock, flags);
@@ -1165,6 +1172,10 @@
*/
ap->private_data = pp;
return 0;
+
+out_alloc_failed:
+ mv_free_pool_items(ap);
+ return -ENOMEM;
}
/**
@@ -1179,6 +1190,7 @@
static void mv_port_stop(struct ata_port *ap)
{
mv_stop_dma(ap);
+ mv_free_pool_items(ap);
}
/**
@@ -2825,14 +2837,39 @@
IS_GEN_I(hpriv) ? &mv5_sht : &mv6_sht);
}
+static void mv_destroy_pools(void)
+{
+ if (mv_sg_tbl_pool)
+ dma_pool_destroy(mv_sg_tbl_pool);
+ if (mv_crpb_pool)
+ dma_pool_destroy(mv_crpb_pool);
+ if (mv_crqb_pool)
+ dma_pool_destroy(mv_crqb_pool);
+}
+
static int __init mv_init(void)
{
+ /* Ideally, a device (second parameter) would "own" these pools.
+ * But for maximum memory efficiency, we really need one global
+ * set of each, shared among all like devices. As below.
+ */
+ mv_crqb_pool = dma_pool_create("mv_crqb_q", NULL, MV_CRQB_Q_SZ,
+ MV_CRQB_Q_SZ, 0);
+ mv_crpb_pool = dma_pool_create("mv_crpb_q", NULL, MV_CRPB_Q_SZ,
+ MV_CRPB_Q_SZ, 0);
+ mv_sg_tbl_pool = dma_pool_create("mv_sg_tbl", NULL, MV_SG_TBL_SZ,
+ MV_SG_TBL_SZ, 0);
